LoGRA cuts RL training memory by 45.7%, enabling 27B RL on a single 8-GPU node

青稞AI · wechat · 2026-10-12

LoGRA tackles the memory bottleneck of RL fine-tuning large models. Instead of freezing the base model and training a LoRA, it accumulates low-rank gradients directly during backprop without storing full gradient matrices, rotating random projections each step while writing updates back to the original model — avoiding the fixed low-rank subspace constraint. A predicted-KL estimate modulates step size to prevent overshooting policy updates.

Results: up to 45.7% training memory savings; RL on a 27B model runs on a single 8-GPU node with 1,100+ stable steps where standard Adam OOMs. Code open-sourced on top of Molt; paper at arXiv 2610.06647.

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